We have just returned from a dreamy week on the Island of Kefalonia in Greece. There is much about the island that makes for interesting contextual analysis of buildings and the how they suit the climate and way of life on the island.
CLIMATE
A typically Mediterranean climate with hot dry summers (up to 35C) and cold wet winters (lows of 6C). These extremes typically mean that cooling and solar-exclusion is required in the summer and heating and solar-inclusion is required in the colder months.
LOCAL ECONOMY
Residents on the island make a living though various industries – in the thriving tourist trade (hotels, restaurants, shops, excursions); or farming olives – beautiful old trees have been tended for literally thousands of years; wine making; farming of crops, goats, sheep and some cattle.
Living off the land is quite common as the island yields all sorts, from vegetables to olives, honey and animal products – fish & goats being most abundant.
TRANSPORT
Ferries link some of the key town on the island as well as to other local islands. There is a basic bus service on the island which is particularly helpful for the islands many aged folk.
As tourists, we needed to hire a car to get around, or take taxis and the bus routes are limited and buses quite infrequent.
Wind power:
I noticed that a number of buildings did have solar thermal panels to make use of the abundant solar energy, and a few had domestic scale wind turbines.
EDF Energies Nouvelles have a 30MW wind farm positioned on the hilly centreparts of the island which seemed to be constantly active. The company owns 90% with the remaining 10% held privately. (Source)
Now I don’t have access to the efficiency of the wind farm but if I was to say that the wind conditions for optimum yield of electricity was only good half of the time (quite possible over a year), the 30MW farm would generate: 4380hrs x 30MW = 131 400MWh.
Assuming an average annual consumption per capita of 5500kWh, this farm supplies enough energy for almost 24000 people. Given that the island has around 33000 inhabitants, this is a good effort towards a completely green energy solution.
What my calculations don’t consider are the number of tourists that occupy the island over the summer, and also the non-domestic energy use of the island. But this at least gives one an idea of how the output of this wind farm may be used.
Solar farms:
There are a few solar electric farms on the island which I would guess are privately owned by hotels to service the needs of these buildings. Especially relevant as the months with the greatest energy demand – tourist season, correlate with the months of greatest solar irradience – long hot summer days.
Further reading –
Thesis on domestic energy consumption in Greece
Power and energy consumption explained
TYPICAL CONSTRUCTION
Kefalonia is prone to tremors and earthquakes and a particularly devastating earthquake in 1953 reduced almost all buildings to rubble (save for the northern village of Fiscado). Since then building have to withstand tremors up to 7.5 on the richter scale. As such, most of the buildings are now built in a concrete bunker style. Strong concrete structure with clay brick infill.
The island is an abundance of lightly coloured sandstone. It was this stone that historically provided the base for all structures and many of these are still visible as ruins around the island.
The stone is still used in modern construction but generally only as cladding or as retaining walls. It is beautiful the way it just roots the buildings to the island though. Golden, authentic, abundant.
Walls and roofs are typically UNINSULATED, relying on the building materials for all regulation of indoor temperature.
ROOFING: Terracotta tiles on timber substructure
WALLS: Concrete structure with clay brick infill
FLOORS: Concrete floor slab
WINDOWS: Double glazed in aluminium frames
SOLAR STRATEGIES
Most houses have external shutters which are perfect for excluding the harsh summer sun even before it enters the building. Adjustable louvers are useful to allow natural ventilation through the dwelling.
Most modern buildings have double glazed windows as a defense against the cold. With temperatures as low as 6C.
By way of a bit of a case study, I will elaborate on the design and construction of the hotel we stayed in LEIVATHO HOTEL, on the South West of the Island. The hotel received the Architectural award for best building in Greece during 2011/2012.
Leivatho Hotel’s commitment to the environment is reflected in the water management, its recycling policy including composting, the use of organic locally produced food and the use of solar energy for water heating. A water recycling system cleans shower and bath water purely biomechanically and produces water which is re-used in the toilet and garden. Water consumption is lowered by up to 50%, which combined with the local flora contributes towards the conservation of a precious natural resource.
Eco- friendly food is served in an ever changing morning buffet, focusing on local specialties and products. Leivatho Hotel also uses 100% cotton linen and offers natural bulk soaps and amenities to its guests. – Hotel Website
Particular sustainable design features I noticed:
- Local workforce used during construction.
- Materials sourced locally where possible – use of Island stone & concrete
- Double glazed windows to shield against the cold and to retain coll air-conditioned air during summer
- Thermal massing of concrete and stone regulates internal temperature. Particularly cood for natural cooling in summer, but also retains mechanical cooled and heated air well.
- The airconditioning will not activate unless all windows are firmly shut
- key-card to activate electricity and this is all switched off when no one is home
- Shaded balconies also shade windows to kitchen and living areas
- Local produced use in hotel meals – herbs and vegetables
- Air curtains to all main building doorways
- Beautiful gardens encourage an abundance of animal and insect life
- Gardens are irrigated only at night when evaporation is minimized
- Roof garden over main building
- All toilet paper is binned rather than flushed (a system used all over the island). Toilet tissue can be recycled and the treatment of sewage is thus simplified greatly.
- Hotel serves local community through employment
Opportunities for further energy and resource efficiency:
- Rainwater collection and reuse. The zinc roofing is perfect for rainwater collection. Wet winters and sudden heavy downpours the rest of the year could definitely be sequestered and stored for garden irrigation and filtered for laundry use or toilet flushing.
- External shutters. I noticed quite a few retro-fitted blinds to windows in the main building which suggest a bit of an oversight here. The contemporary design of the abnormally shaped windows make solar control difficult. Another solution would be to use horizontal external shading.
- Ceiling fans could be used for cooling in the spring and autumn where it is not so hot that air-conditioning is necessary but some additional cooling source would be good to assist thermal comfort. Occupants may well just use the air-con when it is not actually necessary but this obviously has a much great carbon emission level that a fan.
Kefalonia is a beautiful island with warm, friendly people. The lifestyle is relaxed and the land seems to produce much of what is required to sustain life on the island without putting it’s resources under stress. I am encouraged to see that renewable energy options are on the increase, and the simplicity of the lifestyle reminds us tourists that we do not need much to live comfortably and happily. I definitely hope to return one day!
Sustainable Building Design 